Public Comment is a vital part of our multistakeholder model. It provides a mechanism for stakeholders to have their opinions and recommendations formally and publicly documented. It is an opportunity for the ICANN community to effect change and improve policies and operations.
[ Speaking as an individual only.]
As the author of a draft in the IETF which originally proposed this (https://datatracker.ietf.org/doc/pdf/draft-wkumari-dnsop-internal-00), and one of the primary authors of ICANN SSAC113, I fully support the IANA's proposed string.
In addition to meeting the criteria in SAC113 (as demonstrated by .internal being used in the examples) .internal is currently the highest used undelegated TLD on the ICANN Magnitude page (https://magnitude.research.icann.org/) other than .local.
.local cannot be used for this purpose, as it is already in use by mDNS / Apple's Bonjour protocol, and there is special handling for this in many devices.